Identification of Factors Associated with Biofilm Formation Ability in the Clinical Isolates of Helicobacter pylori

Document Type : Research Paper


1 Department of Microbiology, Faculty of Biological Sciences, Alzahra university, Vanak, Tehran, Iran.

2 Department of Microbiology, Faculty of Biological Sciences, Alzahra University, Vanak, Tehran, Iran.



Background: A few reports confirm the ability of Helicobacter pylori to form biofilm. However, conclusive data do not exist concerning the factors that favor this ability.
Objectives: Evaluation of the factors associated with the biofilm formation ability of H. pylori including bacterial, physical and chemical, and environmental factors was the research’s aim.
Materials and Methods: H. pylori isolates from gastric biopsy specimens of patients infected chronically were screened for biofi lm formation ability. Association of bacterial properties such as motility, auto-aggregation, cell hydrophobicity, and extracellular polymeric substances (EPS) with in vitro biofilm formation ability of H. pylori was evaluated. The effects of environmental factors such as growth-medium, temperature, oxygen-tension, pH, β-cyclodextrin, gastric secreted mucins, and sub-inhibitory concentration of amoxicillin were also evaluated.
Results: Ability of clinical H. pylori isolates to form biofi lm in was quantitatively compared. The coccoid shape H. pylori cells were observed by scanning electron microscopy, the images were illustrative of the attachment of cells to form microcolony. The levels of hydrophobicity, motility and auto aggregation of two isolates with highest and lowest biofilm formation ability were the same. However, the signifi cant role of mucins (P < 0.05) in elevating the biofi lm formation was observed. Other factors infl uencing biofi lm formation were: pH, atmosphere and sub-MIC of antibiotics.
Conclusion: Mucins have a significant role in elevating the biofilm formation, also pH, atmosphere and sub-MIC of antibiotics influence biofilm formation.


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